232 GEO. H. BISHOP 
the lower portion of the U, at the base of the gland, thus uniting 
the ectodermal and mesodermal parts. Zander notes that the 
lumen of the ejaculatory duct does not become continuous with 
that of the gland until the contained fluids burst through the thin 
partition at the time of emptying of the secretions (see diagrams, 
pl. 1, and pl. 3, figs. 7-10). (‘Die Beriihrungstelle, an der 
beide Kanalsysteme [of duct and gland], anscheinend bis zur 
Samenentleerung blind aneinander stossen,”’ etc.) He leads one 
to infer that at the maturity of the drone (text fig. 2, A, b) the 
bulb of the penis, acting as a spermatophore, receives this secre- 
tion. Shafer, without noting this partition, infers that the 
sperms remain in the vesicle or the base of the gland until copu- 
lation, and do not pass into the penis bulb, but at the time of 
copulation are carried through the bulb in the ejaculatory duct 
(text fig. 2, C). 
The accessory or mucous gland (text fig. 1, d, and pl. 1), 
developing from the blind recurved end of the vas deferens 
fundament, enlarges into a gourd-shaped body, lined with 
columnar glandular epithelium and enclosed by three muscle 
layers. These layers are an external longitudinal, a medial 
circular, and an inner layer which consists of three longitudinal 
bundles of fibers, extending from the base of the gland more 
than half way to its tip. The musculature is heaviest at the 
base, 1e., around the entrance of the ejaculatory duct, and 
attenuates toward the distal end. The whole is enveloped by a 
thin structureless membrane well supplied with tracheae. As 
the gland’s lumen becomes filled with the secreted mucus, its 
distal end assumes a bulbous contour. The three muscle tracts 
of the inner layer cause an infolding of the glandular lining of 
the organ into three corresponding ridges, giving a cross-section 
of the lumen the shape of a clover leaf (pl. 1, fig. 3). 
The seminal vesicle (text fig. 1, e, and pl. 1, e), like the gland, 
is lined with glandular epithelium, here thrown into ridges 
(KXoschevnikov, “in Ringwalzen eingereiht”’). There are two 
muscle layers surrounding it, an outer longitudinal and an inner 
circular layer. These correspond to the outer two of the three 
layers of muscle of the mucous gland. A membranous envelope 
